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Search Results: 1 - 10 of 18896 matches for " Jingjing Peng "
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Error Analysis of Approximate Calculation of Voltage Divider Biased Common-Emitter Amplifier  [PDF]
Xinwu Chen, Jingjing Xue, Shuangbo Xie, Wenxia Huang, Peng Wang, Ke Gong, Lijuan Zhong
Circuits and Systems (CS) , 2017, DOI: 10.4236/cs.2017.810017
Abstract: Voltage divider biasing common emitter amplifier is one of the core contents in analog circuit curriculum, and almost all of traditional textbooks apply approximate calculation method to estimate all characteristic parameters. In calculating quiescent point, transistor base current is generally ignored to get the approximate base potential and emitter current, then other operating parameters, and AC small signal parameters can be acquired. The main purpose of this paper is to compare traditional and Thevenin equivalent methods and to get the difference of the two methods. A Formula is given to calculate the error of the traditional method. Example calculating reveals that the traditional method can generate an error about 10%, and even severe for small signal amplifier with higher quiescent point.
Riesz Means of Dirichlet Eigenvalues for the Sub-Laplace Operator on the Engel Group  [PDF]
Jingjing Xue
Advances in Pure Mathematics (APM) , 2013, DOI: 10.4236/apm.2013.39A2001
Abstract:

In this paper, we are concerned with the Riesz means of Dirichlet eigenvalues for the sub-Laplace operator on the Engel group and deriver different inequalities for Riesz means. The Weyl-type estimates for means of eigenvalues are given.

The Exploration of Commercial Banks Serving to Technology Innovation Enterprises  [PDF]
Jingjing Gao
Technology and Investment (TI) , 2016, DOI: 10.4236/ti.2016.74017
Abstract:
This paper reviews the commercial banks’ previous exploration and attempt in the service of scientific and technological innovation enterprises. And afterwards, as now the government has officially launched policies and delineated pilot institutions and areas to carry out the investment and lending linkage business, this paper discusses the opportunities and challenges associated with commercial banks to engage in the investment and lending linkage business. Finally, this paper puts forward relevant proposals for commercial banks to serve technology innovation enterprises. Through post-event reviews and present discussions, hopefully this paper can provide some references for commercial banks to carry out the investment and linkage business.
Crowding-Out Effect of Exports on Domestic Consumption: An Analysis Based on Panel Data of Several Industries in China  [PDF]
Jingjing Li
Modern Economy (ME) , 2017, DOI: 10.4236/me.2017.82011
Abstract: This paper tries to use the data of 1998-2014 about nine departments (department of food, beverage and tobacco, department of fabric and clothing, department of car and motorcar and relative spare and accessory parts, department of medicine and the medical machine, department of culture, sports and relative equipment, minerals, building materials and chemical products division, house appliances division, computer auxiliary equipment division and else departments) to make the regression by Eviews 8.0. We find that department of food, beverage and tobacco and department of car and motorcar and relative spare and accessory parts, department of medicine and the medical machine, department of culture, sports and relative equipment do have crowding-out effect of exports on domestic consumption. Finally, in response to the policy of expanding the demand by analyzing the empirical result, we provide some recommendations from the perspective of export trade.
Investment Analysis about China’s IT Company—The Tencent Holdings Limited  [PDF]
Jingjing Che
Modern Economy (ME) , 2018, DOI: 10.4236/me.2018.96072
Abstract: As one of the most huge and potential markets in the world, China has a series of powerful IT companies, such as Tencent, Alibaba, and Xiaomi and so on. Based on such a market and huge population, these companies have very good future in developing and making profits. As a result, studying on them becomes more and more important for the market to know how these companies develop and how their stocks change. This paper focuses on the developing trend of Tencent and tries to provide a valuable investment suggestion for the market. At last, this paper finds that Tencent, as one of the biggest IT companies in China, has very great developing potential with its achievements in the game industry. The main contributions of this paper are that it has found future developing points of Tencent in the game industry and that it points out a new developing power in IT industry, the Entertainment power. The main limitation of this paper is that it has only checked one IT company, the Tencent, instead of comparing different companies to show how Tencent gets benefits from game industry.
An Approach to the Production of Soluble Protein from a Fungal Gene Encoding an Aggregation-Prone Xylanase in Escherichia coli
Yilin Le,Jingjing Peng,Huawei Wu,Jianzhong Sun,Weilan Shao
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0018489
Abstract: The development of new procedures and protocols that allow researchers to obtain recombinant proteins is of fundamental importance in the biotechnology field. A strategy was explored to overcome inclusion-body formation observed when expressing an aggregation-prone fungal xylanase in Escherichia coli. pHsh is an expression plasmid that uses a synthetic heat-shock (Hsh) promoter, in which gene expression is regulated by an alternative sigma factor (σ32). A derivative of pHsh was constructed by fusing a signal peptide to xynA2 gene to facilitate export of the recombinant protein to the periplasm. The xylanase was produced in a soluble form. Three factors were essential to achieving such soluble expression of the xylanase: 1) the target gene was under the control of the Hsh promoter, 2) the gene product was exported into the periplasm, and 3) gene expression was induced by a temperature upshift. For the first time we report the expression of periplasmic proteins under the control of an Hsh promoter regulated by σ32. One unique feature of this approach was that over 200 copies of the Hsh promoter in an E. coli cell significantly increased the concentration of σ32. The growth inhibition of the recombinant cells corresponded to an increase in the levels of soluble periplasmic protein. Therefore, an alternative protocol was designed to induce gene expression from pHsh-ex to obtain high levels of active soluble enzymes.
Metamaterial Electromagnetic Superabsorber with Arbitrary Geometries
Jingjing Yang,Ming Huang,Chengfu Yang,Jinhui Peng,Rong Zong
Energies , 2010, DOI: 10.3390/en3071335
Abstract: The electromagnetic superabsorber that has larger absorption cross section than its real size may be a novel photothermal device with improved solar energy conversion rates. Based on a transformation optical approach, the material parameters for a two-dimensional (2D) metamaterial-assisted electromagnetic superabsorber with arbitrary geometries are derived and validated by numerical simulation. We find that for the given geometry size, the absorption cross section of the superabsorber using nonlinear transformation is larger than that using linear transformation. These transformations can also be specialized to the designing the N-sided regular polygonal superabsorber just by changing the contour equation. All theoretical and numerical results validate the material parameters for the 2D electromagnetic superabsorber we have developed.
Recent advances in studies on dissimilatory Fe(Ⅲ)-reducing microorganisms
异化Fe(Ⅲ)还原微生物研究进展

LI Huijuan,PENG Jingjing,
黎慧娟
,彭静静

生态学报 , 2012,
Abstract: Iron is the fourth most abundant element in the Earth’s crust.Microbially mediated dissimilatory Fe(Ⅲ) reduction is the major process for Fe(Ⅲ) reduction in anoxic environment.This review introduces the classification and the diversity of dissimilatory Fe(Ⅲ)-reducing microorganisms.There are two major groups of Fe(Ⅲ)-reducing microorganisms:one is microorganisms which could conserve energy to support growth from Fe(Ⅲ) reduction,and the other is those which could not conserve energy to support growth from Fe(Ⅲ) reduction.Dissimilatory Fe(Ⅲ)-reducing microorganisms are interspersed throughout Bacteria,Archaea and Fungi and have physiological diversity.Geobacter and Shewanella are the two most well studied genera among all the Fe(Ⅲ)-reducing microorganisms.This also summarizes the strategies that dissimilatory Fe(Ⅲ)-reducing bacteria use to transfer electron to extracellular Fe(Ⅲ) oxide minerals as well as the energy-generating central metabolism models of dissimilatory Fe(Ⅲ)-reducing bacteria.Direct contact,cellular appendage production,electron shuttling and chelation are the four potential strategies for the respiration of dissimilatory Fe(Ⅲ)-reducing bacteria.In Geobacter,acetate and other electron donors are completely oxidized via the tricarboxylic acid(TCA) cycle,generating ATP primarily from oxidative phosphorylation,while substrate-level phosphorylation is the primary source of energy conservation during anaerobic respiration of Shewanella.In addition,the environmental significances of dissimilatory Fe(Ⅲ)-reducing microorganisms are reviewed.Fe(Ⅲ)-reducing microorganisms might be one of the first,if not the first,of microbes involved in microbial respiration in the archaean biosphere,which contributes to the decomposition of organic matter in modern sedimentary environments and inhibition of methane production,exerts a broad range of impacts on the behavior of trace elements and have great potential in the bioremediation and microbial fuel cells.Finally,perspectives in the molecular ecology of dissimilatory Fe(Ⅲ)-reducing bacteria studies are proposed,e.g.the community structure of dissimilatory Fe(Ⅲ)-reducing bacteria in paddy soils,the contribution of dissimilatory Fe(Ⅲ)-reducing bacteria in the C-Fe-N coupling and the mechanism of dissimilatory Fe(Ⅲ)-reducing bacteria in the bioremediation with electrode and solar energy.
An External Cloak with Arbitrary Cross Section Based on Complementary Medium
Chengfu Yang;Ming Huang;Jingjing Yang;Zhe Xiao;Jinhui Peng
PIER M , 2009, DOI: 10.2528/PIERM09110514
Abstract: Electromagnetic cloak is a device which makes an object "invisible" for electromagnetic irradiation in a certain frequency range. Material parameters for the complementary medium-assisted external cylindrical cloak with arbitrary cross section are derived based on combining the concepts of complementary media and transformation optics. It can make the object with arbitrary shape outside the cloaking domain invisible, as long as an "antiobject" is embedded in the complementary layer. The external cloaking effect has been verified by full-wave simulation. Moreover, the effect of metamaterial losses is studied, and small losses less than or equal to 0.01 do not disturb the cloaking effect.
Synthesis of 6H-thiochromeno [3, 4-b] Quinoxaline Derivatives and their Antifungal Activities
Peng Wei,Jingjing Liu,Junjie Ma,Gengliang Yang
Modern Applied Science , 2010, DOI: 10.5539/mas.v4n12p136
Abstract: Objective: To design to synthesize 6H-thiochromeno [3, 4-b] quinoxaline derivatives and evaluate their antifungal activities. Methods: The target compounds were prepared from substituted thiophenol by several steps, and separated by column chromatography. Results: Four new unreported compounds were obtained. All compounds were confirmed by 1 H NMR and MS spectral analysis. Preliminary pharmacological test showed that two compounds both possessed potential antifungal activities. Conclusion: The synthesized 6H-thiochromeno [3, 4-b] quinoxaline derivatives had certain antifungal activities in some tested fungal strains in vitro.
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